I like metal needles (i especially like the new susan bates Velocity needles) --and with 40% off coupons, i often buy needles at Big Box Craft stores.
In my area these stores also sell Clover bamboo needles --not every size, or every length (circ’s) or every style (they have a small selection of DPN’s–but i get what i can at the discount.
same goes for stitch markers, chiba needles, knitting bags, and lot of other accessories.
for Yarn–well the selection (of yarns i want) is smaller–so–i can (and do!) buy some sock yarn (Paton’s kroy, and Patons stretch, and the new Coats & Clarks Heart & Sole (75% wool/25%nylon) but when i want Linen, or Hemp, or well lots of other yarns… i go to the YS. --or i go on line, (or to a yarn & sheep festival…or…)
I don’t use a lot of synthetics… (i use more when i was knitting for kiddies… but nowdays for grandchilden, i use machine washable wools) and while big box stores have better selection (than they did just a few years ago!) LYS are better for yarns…